1. Field of the Invention
This invention relates to and has among its objects the provision of a novel method and apparatus for threshing seeds to remove appendages attached to the seeds. The invention finds particular use in the threshing of seeds armed with appendages that are difficult or impossible to remove with existing seed threshing equipment.
2. Description of the Art
Seeds of some species of plants produce structures during development that serve various functions including protection from damage or aid in dispersal. These structures include awns, beards, tails, hair, fuzz, pappus, bristles, and a variety of other appendages. Since most do not contribute to normal germination of crop seed, that is, do not carry reproductive or nutritive tissue, it is desirable that these appendages be removed by seed-conditioning procedures. Removal of such appendages enhances the cleaning, conveying, and planting of these seeds. Seeds not conditioned in this manner attach to inert material and weed seed contributing to contamination of planting areas. Additionally, because resources such as water, nutrients, and light are used more advantageously by seed which has been freed of appendages, planting such seed results in a saving of time and money for crop producers.
Attachment of appendages to crop seed can also reduce the ability of precision p anters to convey and singulate seed due to attachment of crop seed to each other. Machine planting techniques are important because they allow seed to be efficienty planted at proper intervals and depths. Where crop seed cannot be conditioned for machine planting, the seed must be planted and thinned by hand resulting in greaty increased production costs and decreased planting effciency.
Several types of machines have been designed to remove appendages from crop seed. Spike tooth threshers are commonly used to debeard seed crops including barley, carrot, and grass seed. Belt threshers, which employ two contacting endless belts moving the same direction at different speeds, are used on flower, vegetable, and legume seeds. A number of other designs employ rollers, concaves, hammers, and belts to remove the hulls and appendages from seeds. Seed threshing machines which use rubbing action have the disadvantages that they are not capable of removing appendages such as fuzz, hair, pappus, and the like, and they tend to damage seed. Seed threshing machines which use compressed air have the disadvantages that they have high energy requirements, they produce a dusty environment, and they can only be used for batch processes.
Some types of seed, notably flower seeds such as marigold, gazania, arctotis, and anemone, which are grown primarily for use in the bedding plant and cut flower industries, produce appendages that resist removal by conventional conditioning equipment. This characteristic makes machine planting ineffective resulting in the need for hand planting and thinning, increasing production costs. For some types of seeds, it is necessary to manually remove appendages, cutting them off of each seed individually. An apparatus to mechanically remove appendages from seeds so that they can be conveyed and singulated for precision planting would be of great value to the seed industry.